[MetroMPG]

I put mine dead center up on top of the instrument cluster, in my straight-ahead line of sight. One of the gauges I keep a close eye on is instant fuel economy, and I don't want to frequenly to look down or to the side when driving.

And I stick it in place with velcro because you don't want to leave that on top of the dash on a hot day ... or in plain sight even if it's cool for that matter (thief bait). So I pull it off and drop it under the seat whenever I park.